Heteronuclear cross-relaxation effect modulated by the dynamics of N-functional groups in the solid state under 15N DP-MAS DNP

Park, Heeyong; Uluca-Yazgi, Boran; Heumann, Saskia; Schlögl, Robert; Granwehr, Josef; Heise, Henrike; Schleker, P. Philipp M.

doi:10.1016/j.jmr.2020.106688

Cited by 12 publications

(15 citation statements)

References 35 publications

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“…Therefore, although the detailed nature of the motions underlying the NOE-type processes is presently unclear, one can speculate that it is associated with the disordered glasslike surface state usually encountered in surface phases of mesoporous materials. ,− Beyond the scope of this report, it would be interesting to investigate these motions with temperature-dependent spectral acquisitions as well as deuterium NMR line shape studies of selectively deuterated APTES. We note that Park et al have very recently observed indirect channel polarization transfer to 15 N of primary amines in a DNP-enhanced ssNMR study on benzyl amine and glutamine, which suggests that polarization transfer through cross-relaxation between amine protons to amine-carrying carbons is conceivable.…”

Section: Resultsmentioning

confidence: 62%

“…10,72−74 Beyond the scope of this report, it would be interesting to investigate these motions with temperature-dependent spectral acquisitions as well as deuterium NMR line shape studies of selectively deuterated APTES. We note that Park et al have very recently observed indirect channel polarization transfer to 15 N of primary amines in a DNP-enhanced ssNMR study on benzyl amine and glutamine, 75 which suggests that polarization transfer through cross-relaxation between amine protons to amine-carrying carbons is conceivable.…”

Section: Thementioning

confidence: 64%

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Direct and Indirect Dynamic Nuclear Polarization Transfer Observed in Mesoporous Materials Impregnated with Nonionic Surfactant Solutions of Polar Polarizing Agents

Hoffmann

Bothe²,

Brodrecht³

et al. 2020

J. Phys. Chem. C

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Mesoporous silica materials (SBA-15) with surfaces modified with aminopropyltriethoxysilane (APTES) of two different surface coverages were synthesized, and their structural pore characteristics were analyzed. These two mesoporous silica materials were impregnated with various solutions of radicals in a nonionic surfactant solvent. Differential scanning calorimetry (DSC) analysis of the impregnated mesoporous silica materials confirmed that the surfactant solutions were confined into the pores. Dynamic nuclear polarization (DNP)-enhanced solid-state 13C magic-angle spinning (MAS) NMR spectra recorded for these impregnated mesoporous silica materials showed the presence of superimposed spectra from direct and indirect channel polarization transfer processes not only for the confined surfactant solvent but also for the APTES surface modification. The observation of the indirect channel resonances implies that the surfactant solvents as well as the APTES exhibit molecular motions with correlation times on the order of or faster than the inverse Larmor frequency. Such motions are unexpected at the experimental temperature conditions of ∼120 K in particular for the immobilized APTES. Spectral line widths and intensities of the observed 13C MAS NMR spectra were sensitive to the specific combination of the radical, surfactant solvent, and APTES surface coverage. One particular combination showed identical widths and intensities for the direct and the oppositely phased indirect channel resonances, resulting in a blank spectrum. The differences in line widths and intensities are discussed with respect to the structural organization of the polarizing agent and surfactant within the pores and the complex interplay of intermolecular interactions between these constituents.

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Section: Resultsmentioning

confidence: 62%

Section: Thementioning

confidence: 64%

Direct and Indirect Dynamic Nuclear Polarization Transfer Observed in Mesoporous Materials Impregnated with Nonionic Surfactant Solutions of Polar Polarizing Agents

Hoffmann

Bothe²,

Brodrecht³

et al. 2020

J. Phys. Chem. C

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“…Thus, the absolute deflection from thermal equilibrium is about 2 orders of magnitude larger than what could be achieved by rf saturation. Consequently, large polarization transfer effects can be observed in the presence of molecular dynamics even near 100 K. Such suitable motions include methyl and ammonium reorientation, ,, ring conformational exchange, , and dynamics within polyethers . This peculiar effect, dubbed SCREAM-DNP (specific cross-relaxation enhancement by active motions) can be observed during a direct DNP experiment by reading out the 13 C/ 15 N magnetization by simple Bloch decay (i.e., single-pulse excitation) and results in two overlapping spectral contributions from direct and indirect polarization pathways. ,, …”

Section: Dnp Mechanismsmentioning

confidence: 99%

Dynamic Nuclear Polarization for Sensitivity Enhancement in Biomolecular Solid-State NMR

et al. 2022

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Solid-state NMR with magic-angle spinning (MAS) is an important method in structural biology. While NMR can provide invaluable information about local geometry on an atomic scale even for large biomolecular assemblies lacking long-range order, it is often limited by low sensitivity due to small nuclear spin polarization in thermal equilibrium. Dynamic nuclear polarization (DNP) has evolved during the last decades to become a powerful method capable of increasing this sensitivity by two to three orders of magnitude, thereby reducing the valuable experimental time from weeks or months to just hours or days; in many cases, this allows experiments that would be otherwise completely unfeasible. In this review, we give an overview of the developments that have opened the field for DNP-enhanced biomolecular solid-state NMR including state-of-the-art applications at fast MAS and high magnetic field. We present DNP mechanisms, polarizing agents, and sample constitution methods suitable for biomolecules. A wide field of biomolecular NMR applications is covered including membrane proteins, amyloid fibrils, large biomolecular assemblies, and biomaterials. Finally, we present perspectives and recent developments that may shape the field of biomolecular DNP in the future.

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“…DNP is a technique that allows overcoming the sensitivity problem (Lilly Thankamony, et al, 2017). Recently the effect of spontaneous 1 H-13 C polarization transfer via heteronuclear cross-relaxation due to fast reorientation dynamics in a 13 C or 15 N MAS direct polarization experiment under DNP was discovered (Daube et al, 2016;Hoffmann et al, 2017aHoffmann et al, , 2017bPark et al, 2020). Further investigation showed that cross-relaxation-promoting methyl groups and the resulting Specific Cross Relaxation Enhancement by Active Motions under DNP (SCREAM-DNP) can be used as a tool for selective probing in biomolecules such as RNA and proteins (Mao et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Heteronuclear Cross-Relaxation under Dynamic Nuclear Polarization in Nicotine and Caffeine

et al. 2020

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Dynamic nuclear polarization (DNP) is a technique in magic-angle spinning (MAS) nuclear magnetic resonance (NMR) which leads to sensitivity enhancement and helps to overcome the issue of low polarization in detected nuclei. Recent research showed, that methyl groups, which show active reorientation dynamics and cause heteronuclear cross relaxation at typical DNP temperatures around 100 K, may be used as a pinpoint source of polarization for selective and site-specific probing. In this study, we investigated the cross-relaxation behavior of methyl groups in nicotine and caffeine under DNP. These effects could be useful for investigating receptor/ligand binding.

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Heteronuclear cross-relaxation effect modulated by the dynamics of N-functional groups in the solid state under 15N DP-MAS DNP

Cited by 12 publications

References 35 publications

Direct and Indirect Dynamic Nuclear Polarization Transfer Observed in Mesoporous Materials Impregnated with Nonionic Surfactant Solutions of Polar Polarizing Agents

Direct and Indirect Dynamic Nuclear Polarization Transfer Observed in Mesoporous Materials Impregnated with Nonionic Surfactant Solutions of Polar Polarizing Agents

Dynamic Nuclear Polarization for Sensitivity Enhancement in Biomolecular Solid-State NMR

Heteronuclear Cross-Relaxation under Dynamic Nuclear Polarization in Nicotine and Caffeine

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